Many people are familiar with mobile handsets. Mobile handsets are typically small electronic devices that communicate with a base station to place mobile calls. Many mobile handsets also perform other features in addition to placing mobile calls. For example, some mobile handsets are capable of transmitting data in addition to voice.
A popular feature on many mobile handsets is push-to-talk. With push-to-talk a mobile handset user is able to push a single button to complete a call to a specific mobile handset, or some small number of mobile handsets. The mobile handset acts like a “walkie-talkie.” However, generally, instead of communicating directly to another “walkie-talkie” a mobile handset with push-to-talk typically communicates through a base station to another mobile handset using a single button push to initiate the connection. Additionally, like a “walkie-talkie” when using a mobile handset with push-to-talk, after a user pushes the button they are able to speak without having to wait for the other mobile handset to ring and the other user to answer.
However, some delay between pushing the button and connecting to the other mobile handset may exist. It would be advantageous to try to lower that delay as much as possible. Additionally, while this delay may typically be more noticeable to a user using push-to-talk, or other single button push services, the delay may exist with other mobile handset services including, but not limited to mobile telephone calls and mobile data calls. It would also be advantageous to try to lower the delay as much as possible when using any other communications services that exhibit a delay when communicating with a base station or other transceiver.
One cause of delay when beginning a mobile call, including push-to-talk, and data calls is related to how often a mobile communicates with a base station. Many current mobile handsets are designed to communicate with a base station at specific time intervals. These time intervals are the only time that the mobile handset can begin a mobile call. The longer the delay between intervals, the longer it is likely to take to set up a mobile call. It will be understood by those of skill in the art that the delay will be variable and somewhat random. Depending on when a user initiates a call relative to the next slot cycle. Slot cycle is the time when the mobile handset communicates with the base station. If the user attempts a call close to the next slot cycle, the delay may be relatively short, however, if the user attempts a call just after a slot cycle, the delay may be relatively long.
As stated above one aspect to consider regarding mobile handsets is how often and when the mobile handset should communicate with the base station. Typically, the more often the mobile handset communicates with the base station the faster the mobile handset will be able to respond when the person using the mobile handset attempts to make a call. For example, if the mobile handset communicates with the base station every second, when a user attempts to make a call it will only be one second, at most before the mobile handset is able to communicate with the base station and start the process of placing the call. However, if the mobile handset only communicates with the base station every two seconds, then it could be as long as two seconds before the process of placing the call begins.
So, to speed up placing a mobile call, the mobile handset should communicate with the base station as often as possible. However, communicating with the base station as often as possible has many drawbacks. Transmitting to the base station typically takes power. On a battery-operated device, this can be a critical consideration. Additionally, in many cases the more often a mobile handset communicates with a base station, the fewer mobile handsets that are able to use the base station. This is due to the fact that the base station typically has a limited number of transceivers to communicate with mobile stations. For this reason, each mobile station is given a time when it can communicate with the base station. Multiple mobile handsets are able to communicate with the base station by time-sharing. The more often a mobile handset communicates with the base station, the fewer other mobile handsets can communicate with the base station. For these reasons, and possibly others, the delay between communications between mobile handsets and base stations is not typically made arbitrarily short.
Referring to FIG. 12 more details of communication between mobile handsets and base stations will be discussed. The diagram 700 includes a graph 704. The graph 704 shows when a mobile handset 724 communicates with a base station 722. The communication is shown as electromagnetic signals 720. Communications occur at 707, 709, and 712. It should be noted that this is only one possible example. The time between communications between base station and mobile handset may not always the same.
Typically the slot cycle index is initially negotiated between the base station and the mobile handset. by the manufacturer. The number of clock cycles is known as slot cycle index. Slot cycle index is not a linear. Slot cycle index 0 indicates that communication occurs every cycle. Slot cycle index 1 indicates that a communication occurs every cycle. Referring back to FIG. 12 a slot cycle index 3 indicates that a communication occurs every four cycle. Slot cycle index above slot cycle index 3 are also possible. Slot cycle index timing can be summarized as follows, where x is the slot cycle index:TIME BETWEEN COMMUNICATION=1.28×(2n)For example, for slot cycle index 0 a communication occurs every 1.28 seconds, slot cycle index 1 is a communication every 2.56 seconds, and for slot cycle 2 a communication occurs every 5.12 seconds. Other slot cycle indexes are possible. Additionally, “negative” slot cycles are possible. In one possible implementation of “negative” slot cycles the number “n” in the equation above is a negative number. The use of “negative” slot cycles allows communication to occur more often than every 1.28 seconds.